It is known that, both upper and lower sides of a liquid crystal display screen are required to be detected when the liquid crystal display screen is detected. Generally, the liquid crystal display screen to be detected is operated by a mechanical hand with a suction nozzle, then the liquid crystal display screen to be detected is checked; if the liquid crystal display screen on a suction nozzle side is to be detected without a detection blind zone, the liquid crystal display screen should be further suctioned and lifted from the other side. However, these actions of the mechanical hand such as suctioning and lifting, moving and laying down and so on can cause physical damage to the liquid crystal display screen, resulting in poor product; and the maintenance workload for the mechanical hand itself and its ancillary equipment is heavy; in addition, if both sides of the liquid crystal display screen are detected at one time, the suctioned region cannot be detected, resulting in a detection blind zone.